Age and learning: experimental and clinical aspects.

Memory loss and similar cognitive associated dysfunctions are commonly recognized as being the most serious symptoms of ageing and dementia. In this work, a deterioration of cognitive function which is appreciated in old rats (learning test in a maze--or, in aged humans, memory verbal test) is determined during the measurement of local cerebral blood flow and metabolism. In the animal, the disturbance by the learning test is observed by a decrease of blood flow in the hippocampus, diencephalon, and corpus striatum. In man, the cognitive dysfunctions appear although there is an increase of blood flow in the frontal cortex. These data show a new organization in the ageing brain which only appears during cerebral stimulation.